Definitely, I've ordered some. I've tried 5's and 6's. Both look fine to me but I don't look after WOT. 5's just out. 6's have been knocking about in the tools. I can't see any difference or problems other than my normal too rich... but I wouldn't unless it was horrendous.
These ones are in order from left to right, 1, 2, 3, 4. 1 & 3 look generally darker/more sooty would you say? The non-extended NGK B type plugs barely make it into the chamber anyway, but 1 & 3 also have CHT spark plug thermocouple heat sinks under them. Coincidence? I'm waiting for the postman to bring HT leads, I know I'm a saddo but at HMS Zed it's HT circuit week. . I've removed the crush washers from 2 of the next set.
Or perhaps 3 had been leaking more than 4. Both are probably poor combustion, but 3... Looks worse than 4...
AFR plugged in today snd I'm seeing more sensible numbers than I did with the stock exhaust. Lean with 32 vents/140 mains WOT up to the last few hundred revs. So I guessed it doesn't need 32 vents and refitted 30's. Very low throttle driving rich as a pig. Down in stages from 52 to 45 and could still be leaner but AFAIK 45 is the smallest. With those and 135 mains WOT was ok, a bit rich, but 40-50-60mph was heading for stoich and CHTs climbing so back to the 140's which though bigger than they ought to be and a bit rich WOT I think I'm stuck with. They fast cruise up to 70mph at 13.5-13.8 which it seems to like, cool enough heads. More throttle for hills or acceleration it dips to 13-ish. WOT too rich at around 12 but TBH that's not normally something I do. I'll drive it around like this for a while. Next up those slighly more protruding plugs.
